Methods for treating or preventing fatigue

ABSTRACT

The present invention relates to the use of compounds of the invention for treatment and/or prevention of fatigue, including fatigue associated with diseases or treatments.

RELATED APPLICATIONS

This application is a 35 U.S.C. §371 national phase application of PCTApplication PCT/US2010/039313, filed Jun. 21, 2010, which claimspriority to U.S. Provisional Application No. 61/219,082 filed Jun. 22,2009. The entire content of each of these applications is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to the use of compounds of the inventionfor treatment and/or prevention of fatigue, including fatigue associatedwith diseases or treatments.

BACKGROUND OF THE INVENTION

Fatigue is a weariness or lack of energy that is generally not relievedby rest or sleep. Fatigue is a common side effect of many diseases andconditions, including depression, cancer, multiple sclerosis,Parkinson's disease, Alzheimer's disease, chronic fatigue syndrome,fibromyalgia, chronic pain, traumatic brain injury, AIDS, andosteoarthritis. Fatigue can also result from administration of somemedications or therapies, such as chemotherapy, radiation therapy, bonemarrow transplant, and anti-depressant medications. There have been fewreports of effective treatments for fatigue.

The present invention provides improved methods for treating orpreventing fatigue, e.g., fatigue associated with diseases ortreatments.

SUMMARY OF THE INVENTION

The present invention provides methods of treating and/or preventingfatigue, e.g., fatigue associated with a disease and/or treatment, in asubject, comprising delivering to a subject in need thereof a treatmentor prevention effective amount of a compound of formula I:

or a pharmaceutically acceptable salt or ester thereof, wherein

-   R_(x) is a member selected from the group consisting of hydrogen,    lower alkyl of 1 to 8 carbon atoms, halogen selected from F, Cl, Br    and I, alkoxy containing 1 to 3 carbon atoms, nitro, hydroxy,    trifluoromethyl, and thioalkoxy containing 1 to 3 carbon atoms;-   x is an integer of 1 to 3, with the proviso that R may be the same    or different when x is 2 or 3;-   R₁ and R₂ can be the same or different from each other and are    independently selected from the group consisting of hydrogen, lower    alkyl of 1 to 8 carbon atoms, aryl, arylalkyl, and cycloalkyl of 3    to 7 carbon atoms;-   or R₁ and R₂ can be joined to form a 5 to 7-membered heterocycle    substituted with a member selected from the group consisting of    hydrogen, alkyl, and aryl groups, wherein the cyclic compound can    comprise 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, wherein the    nitrogen atoms are not directly connected with each other or with    the oxygen atom.

In one embodiment of the invention, the fatigue is associated with aparticular disease, disorder, or condition, including withoutlimitation, depression, cancer, multiple sclerosis, Parkinson's disease,Alzheimer's disease, chronic fatigue syndrome, fibromyalgia, chronicpain, traumatic brain injury, AIDS, and osteoarthritis. In anotherembodiment, the fatigue is associated with a particular treatment ortherapy used to treat a disease, disorder, or condition, includingwithout limitation, chemotherapy, radiation therapy, bone marrowtransplant, and anti-depressant medications.

In another aspect of the invention, the compound of Formula I isadministered concurrently with an additional agent or treatment, e.g.,an agent or treatment for treating or preventing a disease, disorder, orcondition.

The present invention is explained in greater detail in the drawingsherein and the specification set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows sleep onset after repeated IP injections of d-amphetamine(A) at light onset (9:00 AM) in C57BL/6J mice. FIG. 1B shows sleep onsetafter a single IP injection of 150 mg/kg test compound (R228060) or 5mg/kg d-amphetamine in three inbred strains of mice (D2=DBA/2J,B6=C57BL/6J, AK=AKR/J, n=7/strain). When expressed as a difference fromthe effect of a saline injection sleep onset after d-amphetaminediffered between D2 and AK mice (asterisk; P<0.05; post-hoc Tukey) (seeinsert). Sleep onset under undisturbed baseline conditions (blacksymbols) are indicated for comparison. Error bars indicate ±1 SEM.

FIG. 2 depicts mean 1 h values of time spent awake for the 3 inbredstrains (B6 black; D2 grey, and AK white symbols). Vertical barsrepresent ±1 SEM; (n=7/genotype). Grey areas mark the dark periods.Lower panel depicts differential effects of test compound (R228060) ascompared to d-amphetamine. Dark-grey squares in upper and middle panelsmark between genotype differences (1-way ANOVA; P<0.05). Diamonds in thelower panel mark significant differences between test compound andd-amphetamine paired t-tests; P<0.05; same color coding as in upperpanel).

FIG. 3 shows the effects of test compound (3, 10, 30 mg/kg i.p.),cocaine (1, 3, 10 mg/kg i.p.), amphetamine (1, 3, 10 mg/kg i.p.) andvehicle (black circles) on sleep-wake states during sixteen consecutivehours following the administration.

FIG. 4 shows the prevalence of insomnia by treatment group and week.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art. For example, features illustrated with respect toone embodiment can be incorporated into other embodiments, and featuresillustrated with respect to a particular embodiment can be deleted fromthat embodiment. In addition, numerous variations and additions to theembodiments suggested herein will be apparent to those skilled in theart in light of the instant disclosure, which do not depart from theinstant invention.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The terminology used in thedescription of the invention herein is for the purpose of describingparticular embodiments only and is not intended to be limiting of theinvention.

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference herein in their entirety.

DEFINITIONS

As used herein, “a,” “an,” or “the” can mean one or more than one. Forexample, “a” cell can mean a single cell or a multiplicity of cells.

Also as used herein, “and/or” refers to and encompasses any and allpossible combinations of one or more of the associated listed items, aswell as the lack of combinations when interpreted in the alternative(“or”).

Furthermore, the term “about,” as used herein when referring to ameasurable value such as an amount of a compound or agent of thisinvention, dose, time, temperature, and the like, is meant to encompassvariations of ±20%, ±10%, ±5%, ±1%, ±0.5%, or even ±0.1% of thespecified amount.

The term “consists essentially of” (and grammatical variants), asapplied to the compositions of this invention, means the composition cancontain additional components as long as the additional components donot materially alter the composition. The term “materially altered,” asapplied to a composition, refers to an increase or decrease in thetherapeutic effectiveness of the composition of at least about 20% ormore as compared to the effectiveness of a composition consisting of therecited components.

The term “treatment effective amount,” as used herein, refers to thatamount of a composition of this invention that imparts a modulatingeffect, which, for example, can be a beneficial effect, to a subjectafflicted with a disorder, disease, or condition, including improvementin the condition of the subject (e.g., in one or more symptoms), delayor reduction in the progression of the condition, and/or change inclinical parameters, disease or condition, etc., as would be well knownin the art. For example, a treatment effective amount can refer to theamount of a composition, compound, or agent that improves a condition ina subject by at least 5%, e.g., at least 10%, at least 15%, at least20%, at least 25%, at least 30%, at least 35%, at least 40%, at least45%, at least 50%, at least 55%, at least 60%, at least 65%, at least70%, at least 75%, at least 80%, at least 85%, at least 90%, at least95%, or at least 100%.

The term “prevention effective amount,” as used herein, refers to thatamount of a composition of this invention that prevents or delays theonset of the disorder, disease, or condition (e.g., in one or moresymptoms) or reduces the severity of the disorder, disease, or condition(e.g., in one or more symptoms) after onset, as would be well known inthe art. For example, a prevention effective amount can refer to theamount of a composition, compound, or agent that delays onset of acondition in a subject by at least 5%, e.g., at least 10%, at least 15%,at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, atleast 45%, at least 50%, at least 55%, at least 60%, at least 65%, atleast 70%, at least 75%, at least 80%, at least 85%, at least 90%, atleast 95%, or at least 100% relative to the absence of administration.

“Treat” or “treating” or “treatment” refer to any type of action thatimparts a modulating effect, which, for example, can be a beneficialeffect, to a subject afflicted with a disorder, disease, or condition(e.g., fatigue), including improvement in the condition of the subject(e.g., in one or more symptoms), delay or reduction in the progressionof the condition, and/or change in clinical parameters, disease orillness, etc., as would be well known in the art.

“Prevent” or “preventing” or “prevention” refer to prevention or delayof the onset of a disorder, disease, or condition (e.g., fatigue) and/ora decrease in the level of fatigue in a subject relative to the level offatigue that would develop in the absence of the methods of theinvention. The prevention can be complete, e.g., the total absence offatigue in a subject. The prevention can also be partial, such that theoccurrence of fatigue in a subject is less than that which would haveoccurred without the present invention.

Methods of assessing fatigue are known in the art and includepsychometric scales such as the Fatigue Severity Scale, the HIV-RelatedFatigue Scale, the Situational Fatigue Scale, the Fatigue AssessmentInstrument, and the Functional Assessment of Chronic IllnessTherapy-Fatigue.

The term “fatigue” is understood in the art and is generally defined asa condition characterized by a lessened capacity for work and reducedefficiency of accomplishment, usually accompanied by a feeling ofweariness and tiredness as well as lack of mental sharpness, focus andconcentration. Fatigue can either be acute or chronic. Fatigue isdistinguished from sleepiness and disorders associated with sleepiness(such as excessive daytime sleepiness and narcolepsy). Fatigue is alsodistinguished from tiredness due to lack of adequate sleep.

“Pharmaceutically acceptable,” as used herein, means a material that isnot biologically or otherwise undesirable, i.e., the material can beadministered to an individual along with the compositions of thisinvention, without causing substantial deleterious biological effects orinteracting in a deleterious manner with any of the other components ofthe composition in which it is contained. The material would naturallybe selected to minimize any degradation of the active ingredient and tominimize any adverse side effects in the subject, as would be well knownto one of skill in the art (see, e.g., Remington's PharmaceuticalScience; 21^(st) ed. 2005). Exemplary pharmaceutically acceptablecarriers for the compositions of this invention include, but are notlimited to, sterile pyrogen-free water and sterile pyrogen-freephysiological saline solution.

The term “pharmaceutically acceptable salts or esters,” as used herein,means nontoxic salts or esters of the compounds employed in thisinvention which are generally prepared by reacting the free acid with asuitable organic or inorganic base or the free base with a suitableorganic or inorganic acid. Examples of such salts include, but are notlimited to, acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate,bitartrate, borate, bromide, calcium, calcium edetate, camsylate,carbonate, chloride, clavulanate, citrate, dihydrochloride, edetate,edisylate, estolate, esylate, fumarate, gluceptate, gluconate,glutamate, glycollylarsanilate, hexylresorcinate, hydrabamine,hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isothionate,lactate, lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate,oleate, oxalate, pamaote, palmitate, panthothenate,phosphateldiphosphate, polygalacturonate, potassium, salicylate, sodium,stearate, subacetate, succinate, tannate, tartrate, teoclate, tosylate,triethiodide, and valerate.

The term “a subject in need thereof,” as used herein, refers to anysubject or patient who currently has or may develop any of the abovesyndromes or disorders, including any condition or disorder whichresults in fatigue, or any other disorder in which the subject's presentclinical condition or prognosis could benefit from the administration ofone or more compounds of Formula I alone or in combination with anothertherapeutic intervention including but not limited to anothermedication.

The terms “fatigue associated with diseases or treatments” and“associated with fatigue” (and similar terms), as used herein, refer toany disease, disorder, condition, treatment, or medication that hasfatigue as one of its symptoms or side effects.

“Concurrently” means sufficiently close in time to produce a combinedeffect (that is, concurrently can be simultaneously, or it can be two ormore events occurring within a short time period before or after eachother). In some embodiments, the administration of two or more compounds“concurrently” means that the two compounds are administered closelyenough in time that the presence of one alters the biological effects ofthe other. The two compounds can be administered in the same ordifferent formulations or sequentially. Concurrent administration can becarried out by mixing the compounds prior to administration, or byadministering the compounds in two different formulations, for example,at the same point in time but at different anatomic sites or usingdifferent routes of administration.

The term “alkyl” denotes a straight or branched hydrocarbon chaincontaining 1-24 carbon atoms, e.g., 1-12 carbon atoms. The alkyl groupcan contain one or more double or triple bonds. Examples of alkyl groupinclude methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl,and the like.

The term “cycloalkyl” refers to non-aromatic cyclic hydrocarbon moietiescontaining 3-24 carbon atoms, e.g., 3-12 carbon atoms. The cycloalkylgroup can contain one or more double bonds. Examples includecyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

By “substituted alkyl” is meant an alkyl in which an atom of the alkylis substituted with, for example, a carbon, nitrogen, sulfur, oxygen,silicon, or halogen atom, or alternatively a nitrogen, sulfur, oxygen,or halogen atom. The term encompasses substituents on alkyl, alkenyl,alkynyl, and cycloalkyl groups.

Examples of substituents that can be attached to any atom of the alkylgroup in a “substituted alkyl” include cyclyl groups, heterocyclylgroups; aryl groups, heteroaryl groups, amino groups, amido groups,nitro groups, cyano groups, azide groups, hydroxy groups, alkoxy groups,acyloxy groups, thioalkoxy groups, acyl thioalkoxy groups, halogengroups, sulfonate groups, sulfonamide groups, ester groups, carboxylicacids, oxygen (e.g., a carbonyl group), and sulfur (e.g., a thiocarbonylgroup). Substituents also include any chemical functional group thatimparts improved water-solubility to the molecule (e.g., carboxylicacid, carboxylic ester, carboxamido, morpholino, piperazinyl,imidazolyl, thiomorpholino, or tetrazolyl groups; both unsubstituted andsubstituted).

The term “alkoxy” denotes an alkyl as defined above linked to an oxygen.

The term “thioalkoxy” denotes an alkyl as defined above linked to asulfur.

The terms “halo” and “halogen” refer to any radical of fluorine,chlorine, bromine or iodine.

The terms “ring” and “ring system” refer to a ring comprising thedelineated number of atoms, said atoms being carbon or, where indicated,a heteroatom such as nitrogen, oxygen or sulfur. The ring itself, aswell as any substituents thereon, can be attached at any atom thatallows a stable compound to be formed.

The term “aryl” refers to an aromatic 5-8 membered monocyclic, 8-12membered bicyclic, or 11-14 membered tricyclic ring system wherein 0, 1,2, or 3 atoms of each ring can be substituted by a substituent. Examplesof aryl groups include phenyl, naphthyl and the like.

The term “heteroaryl” refers to an aromatic 5-8 membered monocyclic,8-12 membered bicyclic, or 11-14 membered tricyclic ring systemcomprising 1-3 heteroatoms if monocyclic, 1-6 heteroatoms if bicyclic,or 1-9 heteroatoms if tricyclic, said heteroatoms selected from O, N, orS, wherein 0, 1, 2 or 3 atoms of each ring can be substituted by asubstituent. Examples of heteroaryl groups include pyridyl, furyl orfuranyl, imidazolyl, benzimidazolyl, pyrimidinyl, thiophenyl or thienyl,quinolinyl, indolyl, thiazolyl, and the like.

The term “arylalkyl” denotes refers to an alkyl as defined abovesubstituted with an aryl as defined above.

The term “heterocycle” refers to a nonaromatic 5-8 membered monocyclic,8-12 membered bicyclic, or 11-14 membered tricyclic ring systemcomprising 1-3 heteroatoms if monocyclic, 1-6 heteroatoms if bicyclic,or 1-9 heteroatoms if tricyclic, said heteroatoms selected from O, N, orS, wherein 0, 1, 2 or 3 atoms of each ring can be substituted by asubstituent. Examples of heterocyclyl groups include piperizinyl,pyrrolidinyl, dioxanyl, morpholinyl, tetrahydrofuranyl, and the like.

Suitable substituents for aryl, heteroaryl, and heterocycle groups arethe same as the substituents for alkyl groups.

The present invention provides methods for treating and/or preventingfatigue in a subject, comprising delivering to a subject in needthereof, a treatment and/or prevention effective amount of a compound ofFormula I:

or a pharmaceutically acceptable salt or ester thereof, wherein

-   R_(x) is a member selected from the group consisting of hydrogen,    lower alkyl of 1 to 8 carbon atoms, halogen selected from F, Cl, Br    and I, alkoxy containing 1 to 3 carbon atoms, nitro, hydroxy,    trifluoromethyl, and thioalkoxy containing 1 to 3 carbon atoms;-   x is an integer of 1 to 3, with the proviso that R may be the same    or different when x is 2 or 3;-   R₁ and R₂ can be the same or different from each other and are    independently selected from the group consisting of hydrogen, lower    alkyl of 1 to 8 carbon atoms, aryl, heteroaryl, arylalkyl, and    cycloalkyl of 3 to 7 carbon atoms;-   or R₁ and R₂ can be joined to form a 5 to 7-membered heterocycle    substituted with a member selected from the group consisting of    hydrogen, alkyl, aryl, and heteroaryl groups, wherein the cyclic    compound can comprise 1 to 2 nitrogen atoms and 0 to 1 oxygen atom,    wherein the nitrogen atoms are not directly connected with each    other or with the oxygen atom.

In one embodiment, R is hydrogen and x=1. In another embodiment, R, R₁,and R₂ are all hydrogen and x=1. In a further embodiment, the compoundhas the structure:

The compounds of Formula I can exist as enantiomers, e.g., R or Senantiomers. Thus, in one embodiment, the compound of Formula I is anenantiomer substantially free of other enantiomers or an enantiomericmixture wherein one enantiomer of the compound predominates(enantiomeric excess). In one embodiment, one enantiomer predominates tothe extent of at least about 60%, e.g., at least about 70%, 80%, 90%,95%, 96%, 97%, 98%, or 99%. In one embodiment, the enantiomer is(R)-(beta-amino-benzenepropyl) carbamate or(O-carbamoyl-(D)-phenylalaninol) or an enantiomeric mixture wherein theenantiomer of (R)-(beta-amino-benzenepropyl) carbamate or(O-carbamoyl-(D)-phenylalaninol) predominates.

An isolated enantiomer is one that is substantially free of thecorresponding enantiomer. Thus, an isolated enantiomer refers to acompound that is separated via separation techniques or prepared free ofthe corresponding enantiomer. The term “substantially free,” as usedherein, means that the compound is made up of a significantly greaterproportion of one enantiomer, e.g., at least about 55, 60, 65, 70, 75,80, 85, 90, 95, 96, 97, 98, or 99% of one enantiomer. Preferredenantiomers can be isolated from racemic mixtures by any method known tothose skilled in the art, including high performance liquidchromatography (HPLC) and the formation and crystallization of chiralsalts, or enantiomers can be prepared by methods described herein.

One compound of Formula I consists of the (D) enantiomer of thestructure shown below wherein R_(x)=R₁=R₂=hydrogen; in the structureshown below the amine group is directed down from the plane of thepaper. This compound is the (R) enantiomer if named by structure and istherefore (R)-(beta-amino-benzenepropyl) carbamate. This compound is thedextrorotary enantiomer and can therefore also be namedO-carbamoyl-(D)-phenylalaninol. The two chemical names may be usedinterchangeably in this specification. In one embodiment, the compoundis in the form of a pharmaceutically acceptable salt, e.g., ahydrochloride salt.

In one aspect of the invention, the fatigue is associated with adisorder, disease, or condition, e.g., depression, cancer, multiplesclerosis, Parkinson's disease, Alzheimer's disease, chronic fatiguesyndrome, fibromyalgia, chronic pain, traumatic brain injury, AIDS, orosteoarthritis. In another embodiment, the fatigue is associated with aparticular treatment or therapy used to treat and/or prevent a disease,disorder, or condition, including without limitation, chemotherapy,radiation therapy, bone marrow transplant, or anti-depressantmedications.

The compounds of Formula I can be synthesized by methods known to askilled artisan. The salts and esters of the compounds of Formula I canbe produced by treating the compound with a suitable mineral or organicacid (HX) in a suitable solvent or by other means well known to those ofskill in the art.

Details of the above reaction schemes for synthesizing compounds ofFormula I as well as representative examples of the preparation ofspecific compounds have been described in U.S. Pat. Nos. 5,705,640,5,756,817, 5,955,499, and 6,140,532, all incorporated herein byreference in their entirety.

From Formula I it is evident that some of the compounds of the inventionhave at least one and possibly more asymmetric carbon atoms. It isintended that the present invention include within its scope thestereochemically pure isomeric forms of the compounds as well as theirracemates. Stereochemically pure isomeric forms may be obtained by theapplication of art known principles. Diastereoisomers may be separatedby physical separation methods such as fractional crystallization andchromatographic techniques, and enantiomers may be separated from eachother by the selective crystallization of the diastereomeric salts withoptically active acids or bases or by chiral chromatography. Purestereoisomers may also be prepared synthetically from appropriatestereochemically pure starting materials, or by using stereoselectivereactions.

Similarly, compounds of the invention containing a double bond can existin the form of geometric isomers, which can be readily separated andrecovered by conventional procedures. Such isomeric forms are includedin the scope of this invention.

During any of the processes for preparation of the compounds of thepresent invention, it may be necessary and/or desirable to protectsensitive or reactive groups on any of the molecules concerned. This maybe achieved by means of conventional protecting groups, such as thosedescribed in Protective Groups in Organic Chemistry, ed. J. F. W.McOmie, Plenum Press, 1973; and T. W. Greene & P. G. M. Wuts, ProtectiveGroups in Organic Synthesis, Third Edition, John Wiley & Sons, 1999, Theprotecting groups may be removed at a convenient subsequent stage usingmethods known in the art.

Other embodiments of the invention include the use, for the preparationof a medicament for the treatment of fatigue, of one of the compounds orenantiomers or enantiomeric mixtures described above or apharmaceutically acceptable salt or ester thereof.

The compounds of this invention include all pharmaceutically acceptablesalt forms thereof. Examples of such salts include those derived frompharmaceutically acceptable inorganic and organic acids and bases.Examples of suitable acid salts include, without limitation, acetate,adipate, alginate, aspartate, benzoate, butyrate, citrate, fumarate,glycolate, hemisulfate, heptanoate, hexanoate, hydrochloride,hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate,malonate, methanesulfonate, nicotinate, nitrate, oxalate, palmoate,pectinate, persulfate, hydroxynaphthoate, pivalate, propionate,salicylate, succinate, sulfate, tartrate, thiocyanate, tosylate andundecanoate. Other acids, such as oxalic, while not in themselvespharmaceutically acceptable, can be employed in the preparation of saltsuseful as intermediates in obtaining the compounds of the invention andtheir pharmaceutically acceptable acid addition salts.

Salts derived from appropriate bases include, without limitation, alkalimetal (e.g., sodium, potassium), alkaline earth metal (e.g., magnesiumand calcium), ammonium and N-(alkyl)₄ ⁺ salts.

Compounds of Formula I include those having quaternization of any basicnitrogen-containing group therein.

Further, the compounds of the invention include prodrugs of thecompounds of Formula I that are converted to the active compound invivo. For example, the compound can be modified to enhance cellularpermeability (e.g., by esterification of polar groups) and thenconverted by cellular enzymes to produce the active agent. Methods ofmasking charged or reactive moieties as a pro-drug are known by thoseskilled in the art (see, e.g., P. Korgsgaard-Larsen and H. Bundgaard, ATextbook of Drug Design and Development, Reading U.K., Harwood AcademicPublishers, 1991).

The term “prodrug” refers to compounds that are rapidly transformed invivo to yield the parent compound of the above formula, for example, byhydrolysis in blood, see, e.g., T. Higuchi and V. Stella, Prodrugs asNovel delivery Systems, Vol. 14 of the A.C.S. Symposium Series and inEdward B. Roche, ed., Bioreversible Carriers in Drug Design, AmericanPharmaceutical Association and Pergamon Press, 1987, both of which areincorporated by reference herein. See also U.S. Pat. No. 6,680,299.Exemplary prodrugs include a prodrug that is metabolized in vivo by asubject to an active drug having an activity of the compounds asdescribed herein, wherein the prodrug is an ester of an alcohol orcarboxylic acid group, if such a group is present in the compound; anamide of an amine group or carboxylic acid group, if such groups arepresent in the compound; a urethane of an amine group, if such a groupis present in the compound; an acetal or ketal of an alcohol group, ifsuch a group is present in the compound; an N-Mannich base or an imineof an amine group, if such a group is present in the compound; or aSchiff base, oxime, acetal, enol ester, oxazolidine, or thiazolidine ofa carbonyl group, if such a group is present in the compound, such asdescribed, for example, in U.S. Pat. No. 6,680,324 and U.S. Pat. No.6,680,322.

The term “pharmaceutically acceptable prodrug” (and like terms) as usedherein refers to those prodrugs of the compounds of the presentinvention which are, within the scope of sound medical judgment,suitable for use in contact with the tissues of humans and/or otheranimals without undue toxicity, irritation, allergic response and thelike, commensurate with a reasonable risk/benefit ratio, and effectivefor their intended use, as well as the zwitterionic forms, wherepossible, of the compounds of the invention.

In one embodiment of the invention, the compounds of the invention areadministered to the subject as needed to treat and/or prevent fatigue.The compound can be administered continuously or intermittently. In oneembodiment, the compound is administered to the subject multiple times aday, e.g. 2, 3, 4, or more times a day. In one embodiment, the compoundis administered to the subject no more than once a day, e.g., once every2, 3, 4, 5, or 6 days, once a week, e.g., no more than once every twoweeks, once a month, once every two months, once every three months,once every four months, once every five months, once every six months,or longer. The compound can be administered 1 hour, 2 hours, 3 hours, 4hours, 5 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 4 days, 5days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, or more prior to theonset of fatigue (e.g., prior to an event that is likely to inducefatigue). The compound can be administered 1 hour, 2 hours, 3 hours, 4hours, 5 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 4 days, 5days, 6 days, 1 week, 2 weeks, 3 weeks, 4 weeks, or more after the onsetof fatigue or an event likely to induce fatigue. In other embodiments,the compound can be administered by any discontinuous administrationregimen. The administration can continue for one, two, three, or fourweeks or one, two, or three months, or longer. Optionally, after aperiod of rest, the compound can be administered under the same or adifferent schedule. The period of rest can be one, two, three, or fourweeks, or longer, according to the pharmacodynamic effects of thecompound on the subject.

The compounds of the invention can be delivered to the subject by anysuitable route, e.g., oral, rectal, buccal (e.g., sub-lingual), vaginal,parenteral (e.g., subcutaneous, intramuscular, intradermal, orintravenous), topical (i.e., both skin and mucosal surfaces, includingairway surfaces) and transdermal administration. The compound isdelivered to the subject at a dose that is effective to treat and/orprevent the fatigue. The effective dosage will depend on many factorsincluding the gender, age, weight, and general physical condition of thesubject, the severity of the fatigue, the particular compound orcomposition being administered, the duration of the treatment, thenature of any concurrent treatment, the carrier used, and like factorswithin the knowledge and expertise of those skilled in the art. Asappropriate, a treatment effective amount in any individual case can bedetermined by one of skill in the art by reference to the pertinenttexts and literature and/or by using routine experimentation (see, e.g.,Remington, The Science and Practice of Pharmacy (21^(st) ed. 2005)). Inone embodiment, the compound is administered at a dose of about 0.01mg/kg/dose to about 300 mg/kg/dose, e.g., about 0.1 mg/kg/dose to about200 mg/kg/dose, about 0.5 mg/kg/dose to about 100 mg/kg/dose, or about0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75,100, 125, 150, 175, 200, 225, 250, 275, or 300 mg/kg/dose. In someinstances, the dose can be even lower, e.g., as low as 0.005 or 0.001mg/m² or lower. In some instances, the dose can be even higher, e.g., ashigh as 500 or 1000 mg/kg/dose or higher. The present inventionencompasses every sub-range within the cited ranges and amounts.

In one embodiment of the invention, the subject is one that hasdeveloped fatigue and the compound is administered to the subject afterthe development of fatigue. In another embodiment, the subject is onethat has not developed fatigue and the compound is administered to thesubject to prevent the occurrence of fatigue. In one embodiment, thesubject is one that is undergoing an event that is likely to result inthe development of fatigue. The compound can be delivered to the subjectprior to the event occurring, concurrently with the event, and/or afterthe event occurs but before the development of fatigue. Events that arelikely to result in the development of fatigue are well known andinclude, without limitation, diseases, disorders, or conditions such asdepression, cancer, multiple sclerosis, Parkinson's disease, Alzheimer'sdisease, chronic fatigue syndrome, fibromyalgia, chronic pain, traumaticbrain injury, AIDS, and osteoarthritis and medications or therapies suchas chemotherapy, radiation therapy, bone marrow transplant, andanti-depressant medications. In one embodiment, the subject hasdepression. In another embodiment, the subject does not have depression.

In one aspect of the invention, the compound of the invention isdelivered to a subject concurrently with an additional agent ortreatment. The additional agent can be delivered in the same compositionas the compound or in a separate composition. The additional agent ortreatment can be delivered to the subject on a different schedule or bya different route as compared to the compound. The additional agent ortreatment can be any agent or treatment that provides a benefit to thesubject, e.g., as treatment and/or prevention for a disease, disorder,or condition that is associated with fatigue. Additional treatmentsinclude, without limitation, surgery, radiation therapy, and bone marrowtransplantation. Additional agents include, without limitation,chemotherapeutic agents, antiemetic agents, analgesic agents (e.g.,opioids and/or systemic local anesthetics), anti-inflammatory agents,antiviral agents, anti-depressant agents, and immunosuppressant agents.

Examples of chemotherapeutic agents include, without limitation,acivicin, aclarubicin, acodazole hydrochloride, acronine, adozelesin,aldesleukin, altretamine, ambomycin, ametantrone acetate,aminoglutethimide, amsacrine, anastrozole, anthramycin, asparaginase,asperlin, azacytidine, azetepa, azotomycin, batimastat, benzodepa,bicalutamide, bisantrene hydrochloride, bisnafide dimesylate, bizelesin,bleomycin sulfate, brequinar sodium, bropirimine, busulfan,cactinomycin, calusterone, caracemide, carbetimer, carboplatin,carmustine, carubicin hydrochloride, carzelesin, cedefingol,chlorambucil, cirolemycin, cisplatin, cladribine, crisnatol mesylate,cyclophosphamide, cytarabine, dacarbazine, dactinomycin, daunorubicinhydrochloride, decitabine, dexormaplatin, dezaguanine, dezaguaninemesylate, diaziquone, docetaxel, doxorubicin, doxorubicin hydrochloride,droloxifene, droloxifene citrate, dromostanolone propionate, duazomycin,edatrexate, eflornithine hydrochloride, elsamitrucin, enloplatin,enpromate, epipropidine, epirubicin hydrochloride, erbulozole,esorubicin hydrochloride, estramustine, estramustine phosphate sodium,etanidazole, etoposide, etoposide phosphate, etoprine, fadrozolehydrochloride, fazarabine, fenretinide, floxuridine, fludarabinephosphate, fluorouracil, flurocitabine, fosquidone, fostriecin sodium,gemcitabine, gemcitabine hydrochloride, hydroxyurea, idarubicinhydrochloride, ifosfarnide, ilmofosine, interleukin II (includingrecombinant interleukin II or rIL2), interferon alfa-2a, interferonalfa-2b, interferon alfa-n1, interferon alfa-n3, interferon beta-Ia,interferon gamma-Ib, iproplatin, irinotecan hydrochloride, lanreotideacetate, letrozole, leuprolide acetate, liarozole hydrochloride,lometrexol sodium, lomustine, losoxantrone hydrochloride, masoprocol,maytansine, mechlorethamine hydrochloride, megestrol acetate,melengestrol acetate, melphalan, menogaril, mercaptopurine,methotrexate, methotrexate sodium, metoprine, meturedepa, mitindomide,mitocarcin, mitocromin, mitogillin, mitomalcin, mitomycin, mitosper,mitotane, mitoxantrone hydrochloride, mycophenolic acid, nocodazole,nogalamycin, ormaplatin, oxisuran, paclitaxel, pegaspargase, peliomycin,pentamustine, peplomycin sulfate, perfosfamide, pipobroman, piposulfan,piroxantrone hydrochloride, plicamycin, plomestane, porfimer sodium,porfiromycin, prednimustine, procarbazine hydrochloride, puromycin,puromycin hydrochloride, pyrazofurin, riboprine, rogletimide, safingol,safingol hydrochloride, semustine, simtrazene, sparfosate sodium,sparsomycin, spirogermanium hydrochloride, spiromustine, spiroplatin,streptonigrin, streptozotocin, sulofenur, talisomycin, tecogalan sodium,tegafur, teloxantrone hydrochloride, temoporfin, teniposide, teroxirone,testolactone, thiamiprine, thioguanine, thiotepa, tiazofurin,tirapazamine, toremifene citrate, trestolone acetate, triciribinephosphate, trimetrexate, trimetrexate glucuronate, triptorelin,tubulozole hydrochloride, uracil mustard, uredepa, vapreotide,verteporfin, vinblastine sulfate, vincristine sulfate, vindesine,vindesine sulfate, vinepidine sulfate, vinglycinate sulfate,vinleurosine sulfate, vinorelbine tartrate, vinrosidine sulfate,vinzolidine sulfate, vorozole, zeniplatin, zinostatin, and zorubicinhydrochloride.

Examples of other chemotherapeutic agents include, but are not limitedto, 20-epi-1,25 dihydroxyvitamin D₃; 5-ethynyluracil; abiraterone;aclarubicin; acylfulvene; adecypenol; adozelesin; aldesleukin; ALL-TKantagonists; altretamine; ambamustine; amidox; amifostine;aminolevulinic acid; amrubicin; amsacrine; anagrelide; anastrozole;andrographolide; angiogenesis inhibitors; antagonist D; antagonist G;antarelix; anti-dorsalizing morphogenetic protein-1; prostatic carcinomaantiandrogen; antiestrogen; antineoplaston; antisense oligonucleotides;aphidicolin glycinate; apoptosis gene modulators; apoptosis regulators;apurinic acid; ara-CDP-DL-PTBA; arginine deaminase; asulacrine;atamestane; atrimustine; axinastatin 1; axinastatin 2; axinastatin 3;azasetron; azatoxin; azatyrosine; baccatin III derivatives; balanol;batimastat; BCR/ABL antagonists; benzochlorins; benzoylstaurosporine;beta lactam derivatives; beta-alethine; betaclamycin B; betulinic acid;bFGF inhibitor; bicalutamide; bisantrene; bisaziridinylspermine;bisnafide; bistratene A; bizelesin; breflate; bropirimine; budotitane;buthionine sulfoximine; calcipotriol; calphostin C; camptothecinderivatives; canarypox IL-2; capecitabine; carboxamide-amino-triazole;carboxyamidotriazole; CaRest M3; CARN 700; cartilage derived inhibitor;carzelesin; casein kinase inhibitors (ICOS); castanospermine; cecropinB; cetrorelix; chlorins; chloroquinoxaline sulfonamide; cicaprost;cis-porphyrin; cladribine; clomifene analogues; clotrimazole;collismycin A; collismycin B; combretastatin A4; combretastatinanalogue; conagenin; crambescidin 816; crisnatol; cryptophycin 8;cryptophycin A derivatives; curacin A; cyclopentanthraquinones;cycloplatam; cypemycin; cytarabine ocfosfate; cytolytic factor;cytostatin; dacliximab; decitabine; dehydrodidemnin B; deslorelin;dexamethasone; dexifosfamide; dexrazoxane; dexverapamil; diaziquone;didemnin B; didox; diethylnorspermine; dihydro-5-azacytidine;dihydrotaxol, 9-; dioxamycin; diphenyl spiromustine; docetaxel;docosanol; dolasetron; doxifluridine; droloxifene; dronabinol;duocarmycin SA; ebselen; ecomustine; edelfosine; edrecolomab;eflornithine; elemene; emitefur; epirubicin; epristeride; estramustineanalogue; estrogen agonists; estrogen antagonists; etanidazole;etoposide phosphate; exemestane; fadrozole; fazarabine; fenretinide;filgrastim; finasteride; flavopiridol; flezelastine; fluasterone;fludarabine; fluorodaunorunicin hydrochloride; forfenimex; formestane;fostriecin; fotemustine; gadolinium texaphyrin; gallium nitrate;galocitabine; ganirelix; gelatinase inhibitors; gemcitabine; glutathioneinhibitors; hepsulfam; heregulin; hexamethylene bisacetamide; hypericin;ibandronic acid; idarubicin; idoxifene; idramantone; ilmofosine;ilomastat; imidazoacridones; imiquimod; immunostimulant peptides;insulin-like growth factor-1 receptor inhibitor; interferon agonists;interferons; interleukins; iobenguane; iododoxorubicin; 4-ipomeanol;iroplact; irsogladine; isobengazole; isohomohalicondrin B; itasetron;jasplakinolide; kahalalide F; lamellarin-N triacetate; lanreotide;leinamycin; lenograstim; lentinan sulfate; leptolstatin; letrozole;leukemia inhibiting factor; leukocyte alpha interferon;leuprolide+estrogen+progesterone; leuprorelin; levamisole; liarozole;linear polyamine analogue; lipophilic disaccharide peptide; lipophilicplatinum compounds; lissoclinamide 7; lobaplatin; lombricine;lometrexol; lonidamine; losoxantrone; lovastatin; loxoribine;lurtotecan; lutetium texaphyrin; lysofylline; lytic peptides;maitansine; mannostatin A; marimastat; masoprocol; maspin; matrilysininhibitors; matrix metalloproteinase inhibitors; menogaril; merbarone;meterelin; methioninase; metoclopramide; MIF inhibitor; mifepristone;miltefosine; mirimostim; mismatched double stranded RNA; mitoguazone;mitolactol; mitomycin analogues; mitonafide; mitotoxin fibroblast growthfactor-saporin; mitoxantrone; mofarotene; molgramostim; monoclonalantibody, human chorionic gonadotrophin; monophosphoryl lipidA+myobacterium cell wall sk; mopidamol; multiple drug resistance geneinhibitor; multiple tumor suppressor 1-based therapy; mustard anticanceragent; mycaperoxide B; mycobacterial cell wall extract; myriaporone;N-acetyldinaline; N-substituted benzamides; nafarelin; nagrestip;naloxone+pentazocine; napavin; naphterpin; nartograstim; nedaplatin;nemorubicin; neridronic acid; neutral endopeptidase; nilutamide;nisamycin; nitric oxide modulators; nitroxide antioxidant; nitrullyn;O6-benzylguanine; octreotide; okicenone; oligonucleotides; onapristone;odansteron; oracin; oral cytokine inducer; ormaplatin; osaterone;oxaliplatin; oxaunomycin; paclitaxel; paclitaxel analogues; paclitaxelderivatives; palauamine; palmitoylrhizoxin; pamidronic acid;panaxytriol; panomifene; parabactin; pazelliptine; pegaspargase;peldesine; pentosan polysulfate sodium; pentostatin; pentrozole;perflubron; perfosfamide; perillyl alcohol; phenazinomycin;phenylacetate; phosphatase inhibitors; picibanil; pilocarpinehydrochloride; pirarubicin; piritrexim; placetin A; placetin B;plasminogen activator inhibitor; platinum complex; platinum compounds;platinum-triamine complex; porfimer sodium; porfiromycin; prednisone;propyl bis-acridone; prostaglandin J2; proteasome inhibitors; proteinA-based immune modulator; protein kinase C inhibitor; protein kinase Cinhibitors, microalgal; protein tyrosine phosphatase inhibitors; purinenucleoside phosphorylase inhibitors; purpurins; pyrazoloacridine;pyridoxylated hemoglobin polyoxyethylene conjugate; raf antagonists;raltitrexed; ramosetron; ras farnesyl protein transferase inhibitors;ras inhibitors; ras-GAP inhibitor; retelliptine demethylated; rhenium Re186 etidronate; rhizoxin; ribozymes; RII retinamide; rogletimide;rohitukine; romurtide; roquinimex; rubiginone B1; ruboxyl; safingol;saintopin; SarCNU; sarcophytol A; sargramostim; Sdi 1 mimetics;semustine; senescence derived inhibitor 1; sense oligonucleotides;signal transduction inhibitors; signal transduction modulators; singlechain antigen binding protein; sizofiran; sobuzoxane; sodiumborocaptate; sodium phenylacetate; solverol; somatomedin bindingprotein; sonermin; sparfosic acid; spicamycin D; spiromustine;splenopentin; spongistatin 1; squalamine; stein cell inhibitor;stem-cell division inhibitors; stipiamide; stromelysin inhibitors;sulfinosine; superactive vasoactive intestinal peptide antagonist;suradista; suramin; swainsonine; synthetic glycosaminoglycans;tallimustine; tamoxifen methiodide; tauromustine; tazarotene; tecogalansodium; tegafur; tellurapyrylium; telomerase inhibitors; temoporfin;temozolomide; teniposide; tetrachlorodecaoxide; tetrazomine;thaliblastine; thiocoraline; thrombopoietin; thrombopoietin mimetic;thymalfasin; thymopoietin receptor agonist; thymotrinan; thyroidstimulating hormone; tin ethyl etiopurpurin; tirapazamine; titanocenebichloride; topsentin; toremifene; totipotent stem cell factor;translation inhibitors; tretinoin; triacetyluridine; triciribine;trimetrexate; triptorelin; tropisetron; turosteride; tyrosine kinaseinhibitors; tyrphostins; UBC inhibitors; ubenimex; urogenitalsinus-derived growth inhibitory factor; urokinase receptor antagonists;vapreotide; variolin B; vector system, erythrocyte gene therapy;velaresol; veramine; verdins; verteporfin; vinorelbine; vinxaltine;vitaxin; vorozole; zanoterone; zeniplatin; zilascorb; and zinostatinstimalamer.

Examples of antiemetic agents include, without limitation,metoclopromide, domperidone, prochlorperazine, promethazine,chlorpromazine, trimethobenzamide, odansteron, granisetron, hydroxyzine,acetylleucine monoethanolamine, alizapride, azasetron, benzquinamide,bietanautine, bromopride, buclizine, clebopride, cyclizine,dimenhydrinate, diphenidol, dolasetron, meclizine, methallatal,metopimazine, nabilone, oxypemdyl, pipamazine, scopolamine, sulpiride,tetrahydrocannabinol, thiethylperazine, thioproperazine, tropisetron,and mixtures thereof.

Examples of analgesic agents include, without limitation, the opioidsallylprodine, alphaprodine, anileridine, benzylmorphine, bezitramide,buprenorphine, butorphanol, clonitazene, codeine, desomorphine,dextromoramide, dezocine, diampromide, diamorphone, dihydrocodeine,dihydromorphine, dimenoxadol, dimepheptanol, dimethylthiambutene,dioxaphetyl butyrate, dipipanone, eptazocine, ethoheptazine,ethylmethylthiambutene, ethylmorphine, etonitazene fentanyl, heroin,hydrocodone, hydromorphone, hydroxypethidine, isomethadone,ketobemidone, levorphanol, levophenacylmorphan, lofentanil, meperidine,meptazinol, metazocine, methadone, metopon, morphine, myrophine,nalbuphine, narceine, nicomorphine, norlevorphanol, normethadone,nalorphine, normorphine, norpipanone, opium, oxycodone, oxymorphone,papaveretum, pentazocine, phenadoxone, phenomorphan, phenazocine,phenoperidine, piminodine, piritramide, proheptazine, promedol,properidine, propiram, propoxyphene, sufentanil, tilidine, and tramadol.

Examples of anti-inflammatory agents include, without limitation,aspirin, ibuprofen, diclofenac, naproxen, benoxaprofen, flurbiprofen,fenoprofen, flubufen, ketoprofen, indoprofen, piroprofen, carprofen,oxaprozin, pramoprofen, muroprofen, trioxaprofen, suprofen, aminoprofen,tiaprofenic acid, fluprofen, bucloxic acid, indomethacin, sulindac,tolmetin, zomepirac, tiopinac, zidometacin, acemetacin, fentiazac,clidanac, oxpinac, mefenamic acid, meclofenamic acid, flufenamic acid,niflumic acid, tolfenamic acid, diflurisal, flufenisal, piroxicam,sudoxicam, isoxicam, celecoxib, rofecoxib, and corticosteroids (e.g.,prednisone, methylprednisolone, dexamethasone).

Examples of antiviral agents include, without limitation, hydroxyurea,ribavirin, IL-2, IL-12, pentafuside, 1-D-ribofuranosyl-1,2,4-triazole-3carboxamide, 9-(2-hydroxy-ethoxy)methylguanine, adamantanamine,5-iodo-2′-deoxyuridine, trifluorothymidine, interferon, adeninearabinoside, protease inhibitors, thymidine kinase inhibitors, sugar orglycoprotein synthesis inhibitors, structural protein synthesisinhibitors, attachment and adsorption inhibitors, and nucleosideanalogues such as acyclovir, penciclovir, valacyclovir, and ganciclovir.

Examples of anti-depressant agents include, without limitation,nefazodone, sertraline, trazodone, nortriptyne, amitriptine, imipramine,paroxetine, fluvoxamine, milnacipran, mirtazapine, mianserin, bupropion,lithium, nefazodone, trazodone, viloxazine, amitriptyline, clomipramine,and fluoxetine.

Examples of immunosuppressant agents include, without limitation,tacrolimus, sirolimus, cyclosporin, methotrexate, cyclophosphamide,azathioprine, mercaptopurine, and mycophenolate.

The present invention finds use in research as well as veterinary andmedical applications. Suitable subjects are generally mammaliansubjects. The term “mammal” as used herein includes, but is not limitedto, humans, non-human primates, cattle, sheep, goats, pigs, horses,cats, dog, rabbits, rodents (e.g., rats or mice), etc. Human subjectsinclude neonates, infants, juveniles, adults and geriatric subjects.

In particular embodiments, the subject is a human subject that hasfatigue and/or is anticipated to experience fatigue. In otherembodiments, the subject used in the methods of the invention is ananimal model of fatigue.

The compounds of the invention described above can be formulated foradministration in a pharmaceutical carrier in accordance with knowntechniques. See, e.g., Remington, The Science And Practice of Pharmacy(21^(st) ed. 2005). In the manufacture of a pharmaceutical formulationaccording to the invention, the compound is typically admixed with,inter alia, an acceptable carrier. The carrier must, of course, beacceptable in the sense of being compatible with any other ingredientsin the formulation and must not be deleterious to the patient. Thecarrier can be a solid or a liquid, or both, and can be formulated withthe compound as a unit-dose formulation, for example, a tablet, whichcan contain from 0.01% or 0.5% to 95% or 99% by weight of the compound.One or more compounds can be incorporated in the formulations of theinvention, which can be prepared by any of the well known techniques ofpharmacy comprising admixing the components, optionally including one ormore accessory ingredients.

The formulations of the invention include those suitable for oral,rectal, topical, buccal (e.g., sub-lingual), vaginal, parenteral (e.g.,subcutaneous, intramuscular, intradermal, or intravenous), topical(i.e., both skin and mucosal surfaces, including airway surfaces) andtransdermal administration, although the most suitable route in anygiven case will depend on the nature and severity of the condition beingtreated and on the nature of the particular active compound which isbeing used.

Formulations suitable for oral administration can be presented indiscrete units, such as capsules, cachets, lozenges, or tablets, eachcontaining a predetermined amount of the active compound; as a powder orgranules; as a solution or a suspension in an aqueous or non-aqueousliquid; or as an oil-in-water or water-in-oil emulsion. Suchformulations can be prepared by any suitable method of pharmacy whichincludes the step of bringing into association the compound and asuitable carrier (which can contain one or more accessory ingredients asnoted above). In general, the formulations of the invention are preparedby uniformly and intimately admixing the compound with a liquid orfinely divided solid carrier, or both, and then, if necessary, shapingthe resulting mixture. For example, a tablet can be prepared bycompressing or molding a powder or granules containing the compound,optionally with one or more accessory ingredients. Compressed tabletscan be prepared by compressing, in a suitable machine, the compound in afree-flowing form, such as a powder or granules optionally mixed with abinder, lubricant, inert diluent, and/or surface active/dispersingagent(s). Molded tablets can be made by molding, in a suitable machine,the powdered compound moistened with an inert liquid binder.

Formulations suitable for buccal (sub-lingual) administration includelozenges comprising the compound in a flavored base, usually sucrose andacacia or tragacanth; and pastilles comprising the compound in an inertbase such as gelatin and glycerin or sucrose and acacia.

Formulations of the present invention suitable for parenteraladministration comprise sterile aqueous and non-aqueous injectionsolutions of the compound, which preparations are preferably isotonicwith the blood of the intended recipient. These preparations can containanti-oxidants, buffers, bacteriostats and solutes which render theformulation isotonic with the blood of the intended recipient. Aqueousand non-aqueous sterile suspensions can include suspending agents andthickening agents. The formulations can be presented in unit\dose (e.g.,in a syringe or other injection device) or multi-dose containers, forexample sealed ampoules and vials, and can be stored in a freeze-dried(lyophilized) condition requiring only the addition of the sterileliquid carrier, for example, saline or water-for-injection immediatelyprior to use. Extemporaneous injection solutions and suspensions can beprepared from sterile powders, granules and tablets of the kindpreviously described. For example, in one aspect of the presentinvention, there is provided an injectable, stable, sterile compositioncomprising one or more compounds, in a unit dosage form in a sealedcontainer. The compound is provided in the form of a lyophilizate whichis capable of being reconstituted with a suitable pharmaceuticallyacceptable carrier to form a liquid composition suitable for injectionthereof into a subject. The unit dosage form typically comprises fromabout 1 μg to about 10 grams of the compound. When the compound issubstantially water-insoluble (e.g., when conjugated to a lipid), asufficient amount of emulsifying agent which is physiologicallyacceptable can be employed in sufficient quantity to emulsify thecompound in an aqueous carrier. One such useful emulsifying agent isphosphatidyl choline.

Formulations suitable for rectal administration are preferably presentedas unit dose suppositories. These can be prepared by admixing thecompound with one or more conventional solid carriers, for example,cocoa butter, and then shaping the resulting mixture.

Formulations suitable for topical application to the skin preferablytake the form of an ointment, cream, lotion, paste, gel, spray, aerosol,or oil. Carriers which can be used include petroleum jelly, lanoline,polyethylene glycols, alcohols, transdermal enhancers, and combinationsof two or more thereof.

Formulations suitable for transdermal administration can be presented asdiscrete patches adapted to remain in intimate contact with theepidermis of the recipient for a prolonged period of time. Formulationssuitable for transdermal administration can also be delivered byiontophoresis (see, for example, Pharm. Res. 3:318 (1986)) and typicallytake the form of an optionally buffered aqueous solution of thecompound. Suitable formulations comprise citrate or bis\tris buffer (pH6) or ethanol/water and contain from 0.1 to 0.2 M active ingredient.

Other pharmaceutical compositions can be prepared from the compoundsdisclosed herein, such as aqueous base emulsions. In such an instance,the composition will contain a sufficient amount of pharmaceuticallyacceptable emulsifying agent to emulsify the desired amount of thecompound. Particularly useful emulsifying agents include phosphatidylcholines and lecithin.

In addition to compound, the pharmaceutical compositions can containother additives, such as pH-adjusting additives. In particular, usefulpH-adjusting agents include acids, such as hydrochloric acid, bases orbuffers, such as sodium lactate, sodium acetate, sodium phosphate,sodium citrate, sodium borate, or sodium gluconate. Further, thecompositions can contain microbial preservatives. Useful microbialpreservatives include methylparaben, propylparaben, and benzyl alcohol.The microbial preservative is typically employed when the formulation isplaced in a vial designed for multidose use. Other additives that arewell known in the art include, e.g., detackifiers, anti-foaming agents,antioxidants (e.g., ascorbyl palmitate, butyl hydroxy anisole (BHA),butyl hydroxy toluene (BHT) and tocopherols, e.g., α-tocopherol (vitaminE)), preservatives, chelating agents (e.g., EDTA), viscomodulators,tonicifiers (e.g., a sugar such as sucrose, lactose, or mannitol),flavorants, colorants odorants, opacifiers, suspending agents, binders,fillers, plasticizers, lubricants, and mixtures thereof. The amounts ofsuch additives can be readily determined by one skilled in the art,according to the particular properties desired.

The additive can also comprise a thickening agent. Suitable thickeningagents can be those known and employed in the art, including, e.g.,pharmaceutically acceptable polymeric materials and inorganic thickeningagents. Exemplary thickening agents for use in the presentpharmaceutical compositions include polyacrylate and polyacrylateco-polymer resins, for example poly-acrylic acid and poly-acrylicacid/methacrylic acid resins; celluloses and cellulose derivativesincluding: alkyl celluloses, e.g., methyl-, ethyl- andpropyl-celluloses; hydroxyalkyl-celluloses, e.g.,hydroxypropyl-celluloses and hydroxypropylalkyl-celluloses such ashydroxypropyl-methyl-celluloses; acylated celluloses, e.g.,cellulose-acetates, cellulose-acetatephthallates,cellulose-acetatesuccinates and hydroxypropylmethyl-cellulosephthallates; and salts thereof such as sodium-carboxymethyl-celluloses;polyvinylpyrrolidones, including for example poly-N-vinylpyrrolidonesand vinylpyrrolidone co-polymers such as vinylpyrrolidone-vinylacetateco-polymers; polyvinyl resins, e.g., including polyvinylacetates andalcohols, as well as other polymeric materials including gum traganth,gum arabicum, alginates, e.g., alginic acid, and salts thereof, e.g.,sodium alginates; and inorganic thickening agents such as atapulgite,bentonite and silicates including hydrophilic silicon dioxide products,e.g., alkylated (for example methylated) silica gels, in particularcolloidal silicon dioxide products. Such thickening agents as describedabove can be included, e.g., to provide a sustained release effect.However, where oral administration is intended, the use of thickeningagents as aforesaid will generally not be required and is generally lesspreferred. Use of thickening agents is, on the other hand, indicated,e.g., where topical application is foreseen.

The present invention is more particularly described in the followingexamples that are intended as illustrative only since numerousmodifications and variations therein will be apparent to those skilledin the art.

EXAMPLE 1

The effects of (R)-(beta-amino-benzenepropyl) carbamate (also known asR228060, hereinafter referred to as test compound) at a dose of 50-150mg/kg PO on various sleep parameters were evaluated in 8 hypocretin cellablated narcoleptic mice (prepororexin/ataxin-3 transgenic) and theirlittermate wild-type mice, and the effects were compared with those ofmodafinil, a reference wake-promoting compound. The test compound showedsignificantly increased bouts of wakefulness in both wild-type andnarcoleptic mice and was able to normalize sleep patterns of narcolepticmice.

Methods

The polygraph signal (EEG and EMG) was captured with SleepSign (KisseiComtech), and the sleep stage was visually scored with 10 sec epoch forwakefulness, non-REM sleep and REM sleep. Scoring criteria are:Wakefulness is characterized by desynchronized low-amplitude, mixedfrequency (>4 Hz) EEG and high EMG activity. Rhythmic alpha (8-9 Hz)wave (with high EMG activities) may also appear. Non-REM ischaracterized by synchronized, high-amplitude, low-frequency (0.25-4 Hz)with reduced EMG activity (compared to wakefulness). EEG activity in REMsleep is similar to that in wakefulness, with desynchronized, mixedfrequency low amplitude waves. Rhythmic alpha (8-9 Hz) wave with reducedEMG activities may also appear. EEG activity during REM sleep is reducedeven further and in many cases, completely absent. Some muscle twitchingmay be apparent in the EMG trace during REM sleep.

Three drug doses of the test compound (50, 100 and 150 mg/kg PO) plusvehicle, were orally administered at ZT 2 (2 hours after light on) orZT14 (2 hours after light off), and the effects on sleep were monitoredfor 6 hours after the drug administration (the sleep data was collectedfor 30 hours after the drug injection, and are available for furtheranalysis). The doses for modafinil were 50 and 200 mg/kg PO (plusvehicle), and modafinil was also administered at ZT 2 and ZT14.

If the polygraph signals of some mice were not sufficient to score thesleep stage with accuracy (especially bad EMG), data from these animalswere excluded, and the minimum of 5 animals (except for the highest doseof the test compound in wild-type mice in dark period, n=4) wereincluded for the data analysis and number of animals were indicated inthe figures.

Effects of test compound and modafinil on the amount of wake, non-REMsleep, REM sleep (cumulative seconds), number of episodes for each sleepstage during 6 hours, and mean wake/sleep-bout lengths (seconds) wereanalyzed in each animal and the mean of each parameter was calculated ineach genotype. The effects of compounds on wake and sleep amounts areuseful to evaluate the wake promoting potency, and the number ofepisodes for each sleep stage and the mean wake/sleep bout length areparameters for evaluating the sleep fragmentation. Amphetamine andmodafinil, two main wake-promoting compounds currently used for thetreatment of EDS associated with various etiologies (narcolepsy,idiopathic hypersomnia and secondary EDS), are known to increase waketime and prolong wake bout length in normal and EDS conditions.

With these data analyses, the wake-promoting and therapeutic effects oftest compound in narcolepsy were evaluated, and the effects werecompared with those of modafinil. A comparison of the effects betweenhypocretin deficient and wild-type mice is very useful in determining ifthe wake-promotion of the test compound is dependent on the availabilityof hypocretins, and if there is a possible change in the sensitivity ofthe receptive mechanisms of test compound in narcoleptic mice due to thehypocretin ligand deficiency.

Results

Effects on sleep during the resting period: Very potent wake-promotingeffects of test compound in both wild-type and hypocretin-deficientnarcoleptic mice were observed. The effects were dose-dependent, andadministrations of 50, 100, and 150 mg/kg PO of test compound inducedcontinuous wakefulness in most wild-type and narcoleptic mice for up to3, 4 and 5 hours, respectively. During this period, Non-REM and REMsleep were completely suppressed. There were no abnormal EEG patternsafter test compound administration, and sleep that occurred after theprolonged wakefulness was normal by polygraphic assessments.

In contrast, the wake promoting effects of modafinil were modest, andthe wake promoting effect of 200 mg/kg of modafinil roughly correspondsto 50 mg/kg of test compound. However, modafinil did not strongly reduceREM sleep after the administration of 50 mg/kg of test compound.Furthermore, test compound potently reduced REM sleep, and thiscontrasts to the effects of modafinil.

Effects on Sleep During the Active Period:

The same experiment was repeated by administrating compounds in theactive period. During the active period, narcoleptic mice spend more insleep than wild-type mice. Wild-type animals typically stayed awake foralmost three hours after vehicle administration. Similar to the effectsobserved during the light period, test compound dose-dependentlyincreased wakefulness in both wild and narcoleptic mice. Wake-promotingeffects in wild-type mice were, however, subtle during the dark perioddue to the high amount of wakefulness at the baseline, and only smalleffects were observed. In contrast, more pronounced wake-promotingeffects were observed in narcoleptic mice, and wake amounts in thesemice after 100 and 150 mg/kg test compound administration were broughtup to the levels of wild-type mice, suggesting that this test compoundnormalizes the sleep/wake amount of narcoleptic mice. Similarly non-REMand REM sleep were reduced in narcoleptic mice by test compound and theamounts of non-REM and REM sleep were also brought down to the levels ofwild-type mice. Similar but much weaker effects were also seen aftermodafinil administration in these mice. Although modafinildose-dependently increased wakefulness in narcoleptic mice, the highdose of modafinil (200 mg/kg) did not bring the wake amount to that ofthe wild-type baseline levels.

EXAMPLE 2

The effects of test compound and d-amphetamine on vigilance states wereexamined in three mouse strains including C57BL/6J, AKR/J and DBA/2J.The test compound showed a genotype-independent increase in wakefulnessand longer wakefulness compared to d-amphetamine.

Methods

At least 7 adult male mice of inbred strains C57BL/6J, AKR/J, and DBA/2Jwere recorded in 2 sessions of 72 continuous hours. The first 24 h ineach session are considered as baseline followed the next day by thesaline injection and the next day by 150 mg/kg of the test compound inthe first session and 5 mg/kg d-amphetamine in the second session. Thetwo sessions were separated by 7 days (wash-out period) and allinjections were intraperitoneal (IP) and performed at light onset (9 am)in a volume of 5 ml/kg.

Results

Dose-Response Effects of d-Amphetamine on Sleep Onset:

C57BL/6J mice were injected each day with 1, 2, 4, 5, and 8 mg/kgd-amphetamine and the sleep latencies calculated (FIG. 1A).D-amphetamine induced wakefulness in a dose-dependent manner between 1and 5 mg/kg but there was no further increase in wakefulness amount at 8mg/kg as compared to 5 mg/kg. Based on these data the dose of 5 mg/kgwas chosen for the comparative experiment. FIG. 1B shows the sleeplatencies after 5 mg/kg d-amphetamine as compared to 150 mg/kg of thetest compound. The test compound at the dose of 150 mg/kg inducedwakefulness for up to 4.5 continuous hours and wake time as referencedto sleep latency after the saline injection showed no genotype effect(FIG. 1B, insert). However and in contrast to the dose-responseexperiment (FIG. 1A), 5 mg/kg d-amphetamine failed to induce the sameamount of wakefulness as 150 mg/kg of test compound. Interestingly,d-amphetamine induced less wakefulness in AK mice (long sleepers) thanin D2 mice (short sleepers), suggesting a genotype-dependent effect ofd-amphetamine (FIG. 1B, insert).

Effects on Vigilance States:

The hourly amounts of wakefulness throughout the 72 h recordings aredepicted in FIG. 2. Although several significant between straindifferences were noticed, test compound (upper panel) and d-amphetamine(middle panel) had very similar effects, except that the test compoundinduced significantly longer wakefulness duration than amphetamine(lower panel).

EXAMPLE 3

The sleep-wake organization in rats after acute administration of thetest compound was examined. Treatment with the test compound at 30 mg/kgstrongly increased active wakefulness at the expense of time spent inlight sleep, deep sleep and REM sleep during the first 3 to 4 hoursafter the administration. Thus the test compound showed central activityimmediately after injection as expressed in changes sleep-wakearchitecture in rats with a functional peak in effect around 2 hrs afteri.p. administration.

Methods

The experiments were carried out on male adult Sprague Dawley rats,supplied by Harlan (Borchen, Germany) weighing 240-260 g at time ofsurgery. Animals were housed in full-view Plexiglas cages (25×33×18 cm)that fit to IVC-racks (individually ventilated cages) located in asound-attenuated chamber. Rats were provided with a micro-chip foridentification purposes and maintained under controlled environmentalconditions throughout the study: 22±2° C. ambient temperature, relativehumidity at 60%, 12:12 light-dark cycle (lights on from 12:00 hrs to00:00 hrs; light intensity ˜100 lux) with standard laboratory food chowand tap water available ad libitum.

Under isoflurane inhalation anesthesia, the rats were mounted in astereotaxic apparatus. The oval area of the scalp was removed, and theuncovered skull was cleared of the periosteum. Three small cavities weredrilled into the cranial bone without perforating the dura to receive 3fixing stainless steel screws (diameter 1 mm) for polygraphic recordingof frontal and parietal electroencephalogram (EEG). Two electrodes wereplaced stereotaxically on each side of the sagittal suture (AP+2 mm, L−2mm; and AP−6 mm, L 3 mm from Bregma, while the third (reference)electrode was screwed over the cerebellum. The incisor bar was −5 mmunder the centre of the ear bar. For the recording of theelectro-oculogram (EOG) and electromyogram (EMG), stainless steel wireswere placed in peri-orbital, and inserted into nuckal muscle,respectively. Electrodes (stainless steel wire, 7N51465T5TLT, 51/46Teflon Bilaney, Germany) were connected to a pin (Future Electronics:0672-2-15-15-30-27-10-0) with a small insert (track pins; Dataflex:TRP-1558-0000) were fitted into a 8 hole connector. Finally, theelectrodes were fixed with dental cement to the cranium. The animalswere housed individually and were allowed to recover for at least oneweek. Ten days after surgery, the animals were habituated for two weeksto the recording procedure in their home cages. The rats were connectedat regular intervals with a cable to a rotating swivel allowing freemovements while EEG, EOG and EMG activities were monitored.

Only rats that complied with the required criteria were used at time oftesting, i.e., weight of animals 300-700 g, good polygraphical signalquality, a wash out period of at least 14 days in case of subject reuse,and no failure in two successive test sessions. For each compound, twoEEG recording sessions were performed in 32 operated animals which wererandomly assigned to 4 treatment conditions (n=8 rats per condition).The first recording session started at 14:00 hrs and lasted 16 hoursafter administration of saline (n=32 rats). The second recording sessionwas performed for the same duration following administration of salineand different doses of test compound (1, 3 and 10 mg/kg), cocaine (3, 10and 30 mg/kg i.p.), or amphetamine (3, 10, 30 mg/kg i.p.). All compoundswere dissolved in saline and administered in a volume of 10 ml/kg bodyweight. An equivalent volume of saline was administered in controlconditions.

Results

The administration of test compound produced significant changes in thedistribution of sleep-wake states (see FIG. 3, left panels). A slightmodification of the sleep-wake architecture was observed throughout the16 hours recording period following the administration of the lowestdose of the test compound (3 mg/kg i.p.). An increase in total lightsleep (+26%, p<0.05) and an increased drive to wakefulness from lightsleep as well as deep sleep (+46%, p<0.001; +15%, p<0.05; respectively)were observed indicating aspects of sleep fragmentation following thisdose of the test compound (p<0.05) (see Table 1).

TABLE 1 Latency (min) Dose ISWS dSWS REM sleep Vehicle (i.p.) 14.2 ± 2.1 38.2 ± 15.0 50.5 ± 8.5  Test Comp. 3 15.6 ± 4.1 42.0 ± 8.5 66.0 ± 11.8(mg/kg i.p.) Test Comp. 10 30.4 ± 7.9 127.2 ± 67.1  87.5 ± 14.5* (mg/kgi.p.) Test Comp. 30  73.6 ± 25.7  174.6 ± 12.3* 251.8 ± 32.0* (mg/kgi.p.) Vehicle (i.p.) 18.6 ± 5.8 27.3.5 ± 8.4   39.0 ± 5.6  Cocaine 1 69.9 ± 51.2  79.3 ± 26.7  74.3 ± 12.1* (mg/kg i.p.) Cocaine 3  41.5 ±9.2*  68.6 ± 7.6* 112.0 ± 12.2* (mg/kg i.p.) Cocaine 10 101.8 ± 6.9*138.8 ± 8.7* 192.1 ± 18.5* (mg/kg i.p.) Vehicle (i.p.) 16.1 ± 3.5  62.3± 11.5 93.4 ± 37.0 Amphetamine 1  140.6 ± 13.4* 161.7 ± 5.3* 208.6 ±14.4* (mg/kg i.p.) Amphetamine 3 228.2 ± 25.0  242.0 ± 19.4* 338.6 ±24.3* (mg/kg i.p.) Amphetamine 10  284.7 ± 56.1* 367.3 ± 5.5* 440.8 ±57.8* (mg/kg i.p.) Values are means ± s.e.m of 8 rats. *p < 0.05:Wilcoxon-Mann-Whitney rank sum tests indicate statistical significancebetween drug and vehicle.

At the dose of 10 mg/kg i.p., test compound produced changes in thesleep wake organization associated with a significant increase in totalduration of light sleep (+24%, p<0.05) and a significant increase inshifts from REM sleep towards active wakefulness (+16%, p<0.05) (seeTables 2 and 3). During the first 90 minutes of the recording period asignificant decrease in deep sleep duration in favor of increase in timespent in active wakefulness was observed (see FIG. 3, left panels)(p<0.05).

TABLE 2 Duration (min) Active Passive Intermediate Light Deep REM Dosewake wake stage sleep sleep sleep Vehicle (i.p.) 313.0 ± 17.2 80.5 ±8.0  5.1 ± 1.0 295.7 ± 21.5 152.7 ± 24.3 96.4 ± 4.5 Test Comp. 3 290.0 ±11.2 79.5 ± 10.7  2.9 ± 0.7*  374.7 ± 16.6* 125.0 ± 24.6 84.0 ± 5.4(mg/kg i.p.) Test Comp. 10 305.5 ± 15.1 73.4 ± 13.2 5.2 ± 0.7  366.6 ±21.2* 104.0 ± 19.3 102.3 ± 4.6  (mg/kg i.p.) Test Comp. 30 371.6 ± 7.7*57.3 ± 4.7* 4.0 ± 1.0  235.8 ± 14.3* 214.9 ± 15.6  72.9 ± 7.3* (mg/kgi.p.) Vehicle (i.p.) 304.3 ± 27.5 54.1 ± 11.5 5.9 ± 1.0 317.1 ± 26.3181.4 ± 20.1 91.2 ± 5.1 Cocaine 1 331.5 ± 41.5 69.8 ± 11.0 6.7 ± 1.0293.2 ± 26.3 162.9 ± 26.3 84.2 ± 8.1 (mg/kg i.p.) Cocaine 3 324.8 ± 18.366.7 ± 8.9  5.7 ± 0.6 303.2 ± 42.5 172.6 ± 34.3 76.7 ± 6.3 (mg/kg i.p.)Cocaine 10 347.3 ± 16.5 55.0 ± 10.4 6.3 ± 1.1 294.6 ± 24.4 171.9 ± 23.874.7 ± 7.5 (mg/kg i.p.) Vehicle (i.p.) 301.0 ± 18.7 74.4 ± 12.0 5.7 ±1.0 371.7 ± 20.6 108.9 ± 23.7 91.5 ± 7.8 Amphetamine 1  382.4 ± 19.6* 50.0 ± 19.6*  4.0 ± 19.6*  242.7 ± 19.6*  188.0 ± 19.6*  88.6 ± 19.6(mg/kg i.p.) Amphetamine 3  441.8 ± 15.7* 43.5 ± 4.4*  4.0 ± 1.0*  187.9± 23.9*  207.6 ± 17.7*  71.4 ± 4.1* (mg/kg i.p.) Amphetamine 10  498.7 ±19.0* 35.6 ± 4.7*  4.0 ± 1.0*  182.0 ± 26.3*  181.2 ± 22.0*  53.6 ± 5.0*(mg/kg i.p.) Values are means ± s.e.m of 8 rats. *p < 0.05:Wilcoxon-Mann-Whitney rank sum tests indicate statistical significanceof the vehicle-drug comparisons

TABLE 3 Shifts (number) Shift from ISWS to Shift from dSWS to Shift fromREMS to Dose AW PW AW PW AW PW Vehicle (i.p.) 148.6 ± 33.1 115.1 ± 45.09.1 ± 6.2 39.1 ± 24.1 81.7 ± 23.1 8.1 ± 5.4 Test Comp. 3  217.8 ± 55.5* 78.1 ± 35.8 9.7 ± 6.6*  6.6 ± 5.9* 78.0 ± 21.6 3.7 ± 3.0 (mg/kg i.p.)Test Comp. 10 204.5 ± 56.4  84.4 ± 40.5 4.2 ± 3.1 12.5 ± 8.5  94.1 ±24.0 8.9 ± 6.7 (mg/kg i.p.) Test Comp. 30  221.9 ± 58.3*  74.2 ± 29.0*8.7 ± 5.3 17.6 ± 12.0  65.1 ± 21.8*  4.1 ± 3.2* (mg/kg i.p.) Vehicle(i.p.) 228.1 ± 56.3 114.5 ± 48.3 10.6 ± 6.5  45.2 ± 28.1 77.5 ± 21.913.2 ± 7.7  Cocaine 1 184.1 ± 48.1 128.6 ± 45.2 10.1 ± 5.6  66.6 ± 48.274.5 ± 21.5 17.0 ± 8.8  (mg/kg i.p.) Cocaine 3 218.5 ± 50.6 142.2 ± 48.510.2 ± 6.7  64.5 ± 42.6 56.0 ± 16.4 10.7 ± 6.9  (mg/kg i.p.) Cocaine 10201.2 ± 53.6 132.6 ± 48.2 10.4 ± 6.2  37.6 ± 23.8 52.3 ± 16.5 9.2 ± 5.8(mg/kg i.p.) Vehicle (i.p.) 204.0 ± 45.7  79.6 ± 40.1 9.1 ± 5.5 10.2 ±8.9  74.2 ± 20.6 6.1 ± 4.3 Amphetamine 1 198.8 ± 50.1  64.4 ± 30.5 11.7± 7.2  37.7 ± 30.0 66.5 ± 19.1 5.8 ± 4.8 (mg/kg i.p.) Amphetamine 3178.7 ± 46.6  62.4 ± 26.1 14.8 ± 7.8  26.6 ± 16.8 59.3 ± 17.8 3.3 ± 2.6(mg/kg i.p.) Amphetamine 10 201.7 ± 66.1  49.0 ± 25.5 9.7 ± 5.9 11.6 ±8.9   50.0 ± 16.2*  2.2 ± 1.9* (mg/kg i.p.) Values are means ± s.e.m of8 rats. *p < 0.05: Wilcoxon-Mann-Whitney rank sum tests indicatestatistical significance of the vehicle-drug comparisons.

At the highest dose (30 mg/kg i.p.) the test compound producedpronounced changes in the distribution of the sleep-wake cycle (see FIG.3). Changes included a marked increase of the total time spent in theactive wakefulness (+19%, p<0.05), a reduction of total time spent inpassive wakefulness (−29%, p<0.05), in light sleep (−20%, p<0.05) aswell as REM sleep (−25%, p<0.05) over the course of the 16-hpost-injection period of the registration (see Table 2). In addition,when compared to total sleep time, test compound induced an increase intime spent in deep sleep and decreased time in REM sleep (p<0.05) (seeTable 3).

A significant enhancement of active wakefulness was observed during thefirst 3 hours following the administration of the test compound(p<0.01). Concomitantly, a large reduction in the time spent in sleepe.g., light sleep (p<0.01), deep sleep (p<0.01) and REM sleep (p<0.01)was observed, followed by a rebound effect, particularly an increase indeep sleep after 3 hours following the administration of the testcompound. The latter effect lasted about 7 hours during the light periodof the recording (see FIG. 1). It should be noted that the onset ofactivity of the test compound was almost immediate, namely around thefirst 30 minutes following administration.

The large increase in total time spent in active wakefulness and thereduction in passive wakefulness, light sleep and REM sleep were due toan increase (+19%, p<0.05), and a decrease (−30%, p<0.05; −23%, p<0.05;−24%, p<0.01) in the number of epochs of these sleep-wake stages,respectively. However, the mean durations of these sleep wake stateswere not modified.

As depicted (see Table 3), the test compound at 30 mg/kg produced anincrease in the number of shifts from light sleep and REM sleep towardswakefulness (p<0.05) and thus suggests indications of sleepfragmentation. Examination of sleep latencies revealed significantchanges following test compound administration (see Table 1). Testcompound at 10 and 30 mg/kg produced a significant lengthening of thelatencies of REM sleep onset.

The present findings show that almost immediately after intraperitonealinjection test compound was centrally active for at least 4 hours with apeak in effect around 2 hours post administration. Only minor effects onsleep-wake architecture were observed at the lowest dose tested of 3mg/kg. Changes in the sleep parameters were observed with the middle (10mg/kg) and more specifically with the higher dose of 30 mg/kg tested.The modifications of the sleep-wake distribution which were most obviousduring the first 3 hours of the registration period were characterizedby a large increase of time spent in active wakefulness, while timespent in passive wakefulness, light sleep, deep sleep and REM sleep wasreduced. Interestingly, test compound produced a rebound effect ofrecovery deep sleep associated with a marked increase in time spent inthis state up to 7 hours.

The effects observed in this comparative study clearly suggest that thetest compound at 30 mg/kg has psychostimulant-like properties at thebeginning of the administration while a consequently following increasein sleep propensity as shown by deep sleep enhancement points towards apotential indirect effect on sleep homeostasis. The overall testcompound profile of effects at 30 mg/kg was remarkably similar to theprofile observed following the administration of amphetamine at thelowest dose tested of 1 mg/kg, both in terms of effect pattern, size andduration.

EXAMPLE 4

The primary objective of this study was to determine the efficacy of 2target doses of test compound (200 and 400 mg/day) in comparison withplacebo during 6 weeks of treatment in adult human subjects withmoderate or severe major depression without psychotic features. Anactive comparator (paroxetine) was included to assist in distinguishinga negative study from a failed study. In addition, an exit interview wasintended to gather information on unexpected benefits of the testcompound in order to refine the clinical development program. One orboth doses of the test compound demonstrated statistically significantlygreater efficacy than placebo on a broad array of secondary efficacyvariables of mood and well-being, suggesting antidepressant activity forthe test compound. In addition, positive effects of the test compound onratings of physical energy/fitness, reduction in sadness or depressionand mental energy or motivation.

Methods

This was a randomized, double-blind, parallel-group, active, andplacebo-controlled, multicenter study conducted in the U.S. (23 centers)and Canada (4 centers). There were 2 phases: a pretreatment phase(screening/washout and a baseline visit) and a 6-week, double-blindtreatment phase. Paroxetine, a positive control, was included toevaluate assay sensitivity. After washout (if needed) of prohibitedsubstances, subjects were randomly assigned (1:1:1:1) to receive thetest compound titrated to a target dose of 200 mg/day or 400 mg/day,matching placebo, or a fixed dose (20 mg/day) of paroxetine. Study drugwas given twice daily for 6 weeks, Efficacy and safety were assessedweekly during the double-blind phase. Subjects completing the studyunderwent an Exit Interview (“Your Health and Well-Being”) and completedan Assessment of Benefits of Clinical-trial Drug-treatment (ABCD)questionnaire (U.S. sites only).

Results

Insomnia was the most common treatment-emergent adverse event in thetest compound groups (200 mg: 24%; 400 mg: 35%), compared with 10% inthe placebo group and 17% in the paroxetine group, but it did not resultin many discontinuations or appreciable rescue medication use. FIG. 4presents the prevalence of insomnia by treatment group and week.Insomnia in the test compound groups, as well as in the paroxetinegroup, was most prevalent during the first week. The duration ofinsomnia was generally similar across the treatment groups.

Results from the U.S. sites of the Exit Interview and the self-rated andblinded ABCD questionnaire on the benefits of treatment in the studyprovided a context for interpreting the results of TC-MDD-201 from thesubject's perspective. The exit interview data indicated that positiveexperiences most frequently included improvements in mood and well-beingin all 4 treatment groups. This was supported by data from the ABCDquestionnaire, in which the most improved aspect of health during thetrial was “reduction in sadness and depression”. Mood, generallyspeaking, was the first symptom to improve, with improvement noticedmostly within the first three weeks of receiving study medication (ExitInterview data).

In general, there were few differences between the 4 treatment groupswithin the 51 items on the ABCD questionnaire. Those that were apparentwere generally most robust between placebo and the active medications(i.e., “physical energy/fitness”, “reduction in sadness or depression”and “mental energy or motivation”) rather than between the activemedications themselves. In post hoc analyses, statistically significantsuperiority to placebo was observed for test compound 200 mg, testcompound 400 mg, and paroxetine on 14, 8, and 14 items, respectively, ofthe questionnaire. However, there were no statistically significantdifferences between test compound 400 mg and test compound 200 mg, orbetween paroxetine and test compound (combined scores for both doses)for any of the 51 items on the ABCD questionnaire.

The foregoing is illustrative of the present invention, and is not to beconstrued as limiting thereof. The invention is defined by the followingclaims, with equivalents of the claims to be included therein. Allpublications, patent applications, patents, patent publications, and anyother references cited herein are incorporated by reference in theirentireties for the teachings relevant to the sentence and/or paragraphin which the reference is presented.

What is claimed is:
 1. A method for treating or preventing fatigue in asubject, comprising administering to a subject in need thereof, atreatment or prevention effective amount of a compound of Formula I:

or a pharmaceutically acceptable salt, ester, or prodrug thereof,wherein R_(x) is a member selected from the group consisting ofhydrogen, lower alkyl of 1 to 8 carbon atoms, halogen selected from F,Cl, Br and I, alkoxy containing 1 to 3 carbon atoms, nitro, hydroxy,trifluoromethyl, and thioalkoxy containing 1 to 3 carbon atoms; x is aninteger of 1 to 3, with the proviso that R may be the same or differentwhen x is 2 or 3; R₁ and R₂ can be the same or different from each otherand are independently selected from the group consisting of hydrogen,lower alkyl of 1 to 8 carbon atoms, aryl, heteroaryl, arylalkyl, andcycloalkyl of 3 to 7 carbon atoms; or R₁ and R₂ can be joined to form a5 to 7-membered heterocycle substituted with a member selected from thegroup consisting of hydrogen, alkyl, aryl, and heteroaryl groups,wherein the cyclic compound can comprise 1 to 2 nitrogen atoms and 0 to1 oxygen atom, wherein the nitrogen atoms are not directly connectedwith each other or with the oxygen atom.
 2. The method of claim 1,wherein R is hydrogen and x=1.
 3. The method of claim 1, wherein R, R₁,and R₂ are all hydrogen and x=1.
 4. The method of claim 1, wherein thecompound of Formula I is:

or a pharmaceutically acceptable salt, ester, or prodrug thereof.
 5. Themethod of claim 1, wherein the compound of Formula I is an enantiomersubstantially free of other enantiomers or an enantiomeric mixturewherein one enantiomer of the compound predominates.
 6. The method ofclaim 5, wherein one enantiomer predominates to the extent of at leastabout 90%.
 7. The method of claim 5, wherein one enantiomer predominatesto the extent of at least about 98%.
 8. The method of claim 5, whereinthe compound is

or a pharmaceutically acceptable salt, ester, or prodrug thereof.
 9. Themethod of claim 1, wherein the fatigue is associated with a disease,disorder or condition.
 10. The method of claim 9, wherein the disease,disorder or condition is selected from the group consisting ofdepression, cancer, multiple sclerosis, Parkinson's disease, Alzheimer'sdisease, chronic fatigue syndrome, fibromyalgia, chronic pain, traumaticbrain injury, AIDS, and osteoarthritis.
 11. The method of claim 1,wherein the fatigue is associated with a treatment or medication. 12.The method of claim 11, wherein the treatment or medication is selectedfrom the group consisting of chemotherapy, radiation therapy, bonemarrow transplant, and anti-depressant treatment.
 13. The method ofclaim 1, wherein the compound is administered concurrently with anadditional agent or treatment.
 14. The method of claim 1, wherein thecompound is administered prior to an event that may result in fatigue,concurrently with an event that may result in fatigue, and/or after theonset of fatigue.
 15. The method of claim 1, wherein the treatment orprevention effective amount of the compound is from about 0.01mg/kg/dose to about 300 mg/kg/dose.